Denosumab

Denosumab reduces fracture risk while you take it, but stopping can cause a dangerous rebound of vertebral fractures.

The evidence for denosumab comes mostly from the FREEDOM trial, a manufacturer-funded study of 7,808 postmenopausal women. It found that 60 mg injected every six months cut new vertebral fractures from 7.2% in the placebo group to 2.3%, a 68% relative reduction [2]. Hip fractures fell from 1.2% to 0.7%, a 40% reduction [2]. These are real clinical outcomes, not surrogate lab values, and the benefit is substantial for women with established osteoporosis.

The problem is what happens when you stop. The drug suppresses bone turnover completely, and when it wears off, the body rebounds. In the FREEDOM extension, 1,001 women who stopped denosumab had a vertebral fracture rate of 7.1 per 100 person-years, compared to 1.2 while on the drug and 3.2 in the original placebo group [3]. More than 60% of those who fractured had two or more vertebral breaks [3]. A UK audit of 579 osteoporosis patients found 1% developed osteonecrosis of the jaw, mostly on denosumab [4]. Delaying a dose beyond 16 weeks raised vertebral fracture risk nearly fourfold [1].

The drug works, but it is a trap. You cannot take a holiday, and stopping without a transition to another agent like a bisphosphonate carries a real risk of multiple vertebral fractures. The manufacturer holds the liability shield, so the injured bear the cost.

My call: denosumab is effective for high-risk osteoporosis, but the rebound fracture risk on discontinuation is serious and well-documented. Only start if you are committed to staying on it or have a plan for transitioning off. Confidence: high for the benefit and the rebound risk.